it's not clear whether they're from the bomb itself or the environment around the bomb. >> but the bomb may have hit other metal objects that then splintered apart? >> this is what i'm hearing, although i certainly don't know that for a fact. the operations that we have performed are identical to the kind of work we would do in the army at a forward surgical team or combat support hospital. >> well, again, we know there is heroism, large and small at all times at mass general, and we thank you so much for joining us. i know you've got at least five surgeries today. we'll let you go back to work. >> thank you very much. >>> and coming up next here, a nation on edge. other cities in america, after the tragedy in boston. and chantix helped me quit. i honestly loved smoking, and i honestly didn't think i would ever quit. [ male announcer ] along with support, chantix (varenicline) is proven to help people quit smoking. it reduces the urge to smoke. it put me at ease that you could smoke on the first week. [ male announcer ] some people had changes in behavior, thinking or mood, hostility, a